The person who is currently in the last qualifying position at a pinball tournament (for example: 16th place out of 16 qualifiers). The Gatekeeper must be sure to rigorously defend the position or work quickly to move higher in the standings.

In games with a wizard mode, it is the one requirement that is much harder than all the others. It is usually the one you complete last before achieving the Wizard Mode, making the other requirements not as relevant.